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Building Block 
und Brick. 

m H iliH 

Concrete Block Office ] 
Sheet & Tin Plate Co., 

Concrete Building Block and Brick 

A Guide to Good Practice 

The object of this booklet is to give the fundamental principles 
underlying the manufacture of concrete building block and brick, so 
that these worthy building units may receive proper recognition. 

At times when there are transportation difficulties, concrete block 
come in for special attention as a building unit because of the many 

One of the buildings of the Minnesota Steel Co. plant at Duluth, Minn., 
constructed of Hydro- Stone block. 

concrete products plants conveniently located throughout the country. 
These fortunate locations, together with the fact that the great bulk 
of materials entering into concrete may be found locally, make it pos- 
sible to secure a high-class building material, requiring little or no 
transportation, near practically any building site. 

Merits of Concrete Block 

Concrete block, made of suitable materials correctly proportioned 
by processes that have been proved good practice, possess the desirable 
qualities of utility, attractiveness and permanence. Like monolithic 
concrete, concrete block and brick, if well made, grow stronger with 


age, and concrete brick or block buildings, like those of monolithic 
concrete, are fireproof, rotproof, ratproof, sanitary, and require the 
minimum of maintenance. 

Concrete block, and in some cases concrete brick, are particularly 
applicable to the construction of many types of buildings that have 
been and are still needed to complete the Government's war building 
program. Factories, machine shops, power houses, houses, apartment 
buildings, all kinds of farm buildings, which includes silos, are built 
of concrete block or concrete brick to the utmost satisfaction of the 

Factory of the Knechtel Furniture Co., Hanover, Ontario, built of Ideal concrete block. 

builder or owner. Representative structures built of concrete block 
or brick, illustrated in this booklet, support the foregoing statement. 

Importance of Good Workmanship 

Nearly everyone knows that concrete is made by mixing portland 
cement, sand, pebbles or crushed stone and water, placing the material 
in some kind of a form and allowing it to remain undisturbed while 
hardening. Many persons, however, do not appreciate the fact that 
some concrete varies greatly in quality from other concrete and that 
for good concrete, whether in the form of block, brick or monolithic, 
best results are obtained only when suitable materials are correctly 


proportioned, mixed, placed and cured or hardened under proper 

Materials Used 

In the manufacture of concrete block or brick, only portland cement 
complying with the specifications of the American Society for Testing 
Materials should be used. The sand and pebbles or broken stone, 
which are called fine and coarse aggregates, should be clean, well 
graded and free from clay, loam or organic matter. Sand is considered 

Concrete block wall construction by use of a type of interlinking concrete block made by 
the Roman Concrete Products Co., Pittsburgh, Pa 

as that material which will pass a *4-inch mesh screen and which will 
be graded downward from that size to very fine particles. If the only 
sand available contains such objectionable materials as clay, loam or 
organic matter, it should be washed before using in a concrete mixture. 
Coarse aggregate usually consists of pebbles, crushed trap rock, 
granite, limestone or crushed blast furnace slag. It also must be well 
graded and free from the impurities or foreign materials above men- 
tioned. In general, all coarse aggregate used for concrete block should 
be retained on a ' 4-inch mesh screen and should pass a 3 4 -inch mesh 


Water used in concrete mixtures must be clean, free from mud, 
silt, alkali, acids, oils or other foreign materials such as discharges 
from factories, sewers, etc. The quantity of water used in concrete 
is of great importance; that is, for certain mixtures there is a definite 
quantity of water that will produce the best possible concrete to secure 
from that mixture. However, the various machines and processes of 
manufacturing block and brick do not always permit use of exactly 
the most desirable quantity of water. 

Consistency of Concrete 

The strongest concrete will result from using only sufficient water 
to produce a stiff, plastic mixture. As some block are made, such a 
mixture cannot be used, and it is not expected that the block made 

One of a number of concrete block buildings built of Hydro-Stone by the Loyal Order of 
Moose at its industrial community. Moose heart. III. 

from a relatively dry mixture of concrete will be as strong as that 
made from a stiff plastic mixture. Nevertheless many block and brick 
manufacturers use less water than would be possible with the type of 
machine employed. Enough water should be used so that the concrete 
will approach that limit of plastic state which will just prevent the 
block from changing its shape when removed from the mold or ma- 
chine. Better results would in general be secured if mixing water, 
when used, were always at a temperature higher than 60 degrees. If 
water colder than 60 degrees is used, setting of the cement, and con- 
sequently hardening of the concrete, is considerably retarded. 


Variations in Surface Texture and Finish 

With the greatly increased popularity of concrete as a building 
material there have been developed many ways of giving to concrete 
block and brick very attractive surfaces. A great deal of objection 
was raised to the earlier and common type of rock-faced block which 
attempted to imitate stone, but which deceived no one. This type is 
not recommended. Various surface finishes may readily be given to 
concrete block or brick, depending on the type of machine used, the 
materials of which the concrete is composed, the manner in which 
concrete is placed in the molds and the final treatment given to the 
finished block or brick after removed from the machine. Both block 








A good example of rock- faced block, a product of the Anchor Concrete Stone Co., 

Columbus, Ohio. 

and brick may be plain, tool-faced, paneled, have an exposed aggregate 
surface, and so on. 

The easiest method of obtaining a plain face block is to use a 
smooth face plate in the machine and work the concrete back from the 
plate while placing, so that no coarse aggregate will show on the face 
of the finished block. Such a surface will be smooth but dull looking, 
although it can be improved by spraying the face of the green block 
with a fine jet of water from a nozzle, which will wash away the film 
of cement on the surface and expose some of the aggregate particles; 
or the same aggregate exposure can be secured by brushing the surface 
with a stiff fiber brush after the concrete has obtained a certain degree 
of hardness, or by rubbing the face with carborundum brick. 


Fine hair checking or crazing may occur on block with smooth 
faces. This, however, will not be noticeable if the block faces are 
tooled so as to form either horizontal or vertical ribbed lines on the 
exposed surface. Machines for this purpose have been developed, 
and block are often treated this way after the concrete has hardened 
for several weeks. 

By far the most attractive sur- 
face finishes are those which are, 
in large part, prearranged when 
mixing and placing the concrete; 
that is, selected aggegates are 
used instead of common sand, at 
least for the face of the block or 
brick, these materials being 
chosen principally because of 
their color. For example: instead 
of using ordinary sand, white 
sand and marble chips or granite screenings, crushed feldspar, mica 
and mica spar, crushed slag, garnet sand and similar colored rock 
materials are used as aggregates. Mixtures are prepared and placed 
in the usual way, then when the concrete has reached the proper 

An example of one of several tooled fin- 
ishes that may be given to concrete block. 

View showing plan and face of the Brandell concrete block. 

degree of hardness for whatever future treatment is to be applied, 
the surface of the block is gone over in one of several ways to secure 
the desired final effect. This may consist of scrubbing with bristle 


brush and water while the con- 
crete is still green, or scrubbing 
with brush and an acid solution 
consisting of 1 part hydrochloric 
acid to 3 or 4 parts of water, to 
remove the cement coating of the 
surface aggregate particles. 

Variations in the texture and 
color of the surface can be se- 
cured by different combinations 
of different colored aggregates. 
Yellow and white marble chips or 
gray granite screenings and blac 

, tht / /. CO 

and the manner in which they are 

that U 



armth and moi- 

: in the 

•.anufactured mu 


[Itype of surface finish secured on 
Hcintyre hollow concrete tilt solely 

by the farm of the imdd. 

k crushed slag combined are ex- 
amples. Often white portland 
cement is used with selected ag- 
gregates, such as white marble 
chips, feldspar, slag, etc. In all 
attempts to secure a distinctive 
surface finish to concrete block or 
k. freakish effects should be 
avoided. It should be remem- 
- d that concrete is a distinct- 
ive building material and should 
andled accordingly. 

Strength of Concrete 
Block and Brick 

■ engtll oi concrete 

building block and brick depends 

upon the quality of the materials 

I 1 hei with proper methods 

block ot the flydto 

ing black and u hite yramti us uyy>> 


tect the concrete from sun and drying winds, as circulation of air 
about the block or brick will cause rapid evaporation of moisture from 
the concrete before the necessary chemical changes or transformation 
of the cement has been completed. It matters but little how moisture 
and warmth are applied so long as the combined condition is secured. 
In commercial block or brick manufacture, however, these conditions 
are usually obtained in steam curing rooms or chambers. Sometimes, 
however, the products are water cured by water spray. The spray 
should not be applied so as to strike the fresh products with any force 

as it would then tend to mar the green 
concrete. By the use of certain types 
of nozzles intended for the purpose, a 
floating mist or fog of spray can be pro- 
duced in the curing rooms or tunnels, 

Flour mill of Ideal concrete block, built by the Omaha Concrete Stone Co., Omaha, Neb. 

which will keep the air saturated with moisture to the required degree 
for proper hardening of the concrete. When the temperature of the 
curing room or chamber drops below 50 degrees, wet steam can be 
employed to advantage, and the best way of introducing steam into 
the curing rooms or chambers is through a perforated pipe laid in a 
trough of water in the floor of the rooms, with the perforations down- 
ward, the pipe being completely submerged. Steam thus passing 
through the water to the interior of the room becomes saturated with 
moisture. Temperatures in the curing or hardening room should 
range from 100 to 120 degrees. Moist steam obtained as above indi- 
cated does not dry out the block but maintains the required degree of 
moisture and warmth. Ordinarily block or brick should remain in the 



curing rooms from three to four days, depending on temperature and 
weather conditions. At the end of that time they may be removed to 
a storage yard or shed where they should remain from twenty to 
thirty days before being laid up in building walls. 

Determining Strength 
by Careful Tests 

Every block or brick manu- 
facturer should have tests made 
on his products to determine 
their strength. This can be ar- 
ranged for either with commercial 
or college laboratories. In this 
way the manufacturer obtains 
knowledge as to the strength of 
his product and thereby definite 
data for comparison with the 
product of other manufacturers. 

Types of Block 

Concrete block are 
made with an air space or 
for the purpose of obtainin 

One type of wall secured by laying up 
Hydro-Stone block, resulting in continuous 
usually a ir space in both directions. 


g insulation. Many patented types of block 

; . ;M 01 types of wall using certain 

^ types of block have been used or 

^r advocated. Providing a dead 

space in the wall of the building 

!■ either by making blocks with air 

b spaces or by laying the blocks so 

that a double wall results, insu- 

^ lates the wall and the building 

interior is less affected by 

B changes of outdoor temperature. 

This insulation, if effectively 

£* secured, prevents condensation on 

■A* the interior of block walls. 

VaHoiU details shouiny the interlock! 
principle of the Myer concrete block. 



Types of Machines or Molds 

Machines or molds now on the market for manufacturing concrete 
block might be classified in groups with respect to the manner in 
which concrete is tamped or compacted in the mold. This in turn 
naturally permits a classification with respect to the consistency of 
concrete used. However, the design of the block and the manner in 
which a machine is operated will determine to a considerable extent 

Concrete block sub-station of the Great Northern Power Co., Duluth, Minn. 

how much water can be added to semi-dry concrete toward the point 
of obtaining a concrete of stiff, plastic consistency for block manufac- 
ture. Different operators using the same machine will use concrete 
varying in consistency dependent upon their skill and experience in 
manufacturing concrete products. 

One process of manufacture permits the use of a wetter concrete 
than any of the others and in this process the machines or molds 
employed use a more than ordinarily wet concrete. Mixtures con- 
taining more water than that which will produce a stiff plastic con- 
sistency should be used only in sand molds, as such molds will take 



Concrete block 

ition, Mooseheart. 111. 

up quickly the excess water. In those methods of manufacture re- 
quiring the use of iron or steel molds, the least amount of water pos- 
sible should be used to obtain the results desired. 

A list of manufacturers of concrete block machines or molds is 
given elsewhere in this booklet. Those intending to engage in the 
manufacture of concrete products should, before taking up such 
manufacture, obtain catalogues from the various manufacturers of 
concrete machinery and study the possibilities of the various machines 

Locomotive shops of the Elgin. JoUei & Eastern Railway Co., Joliet. III., built of Hydro- 

Stone block. 



Concrete block were used in developing the model city of Morgan Park, Duluth, Minn., 
shown above. Walks, streets and alleys also are of concrete. 

with particular reference to the standard practice in concrete block 
manufacture as laid down by the specifications of the American Con- 
crete Institute, adopted April 10, 1917. Intelligent decision can then 
be made on the process or type of machine to be chosen. 

Second Baptist Church. Little Rock, Ark., built of concrete block. Fire destroyed in- 
terior of building March 28, 1918, with no damage to walls, as shown above. 



A common size for concrete building block is 8 inches thick by 
8 by 16-inch face, although there are machines designed to make block 
10 and 12 inches wide, these widths determining the thickness of the 
finished building wall. Other lengths sometimes found are 18, 20, 24 
and 32 inches. In general, concrete block machines are equipped to 
manufacture fractional blocks consisting of *4, J4 and 3 4 lengths. 
These are required to finish out corners and to break joints. The 


L otu rete bloc 

rnyard lot watt. 

actual face dimensions are usually * 4 inch less than stated. This is to 
allow for mortar joints so that when the block are laid up with joints 
equivalent to this J 4 -inch allowance, the surface area occupied by the 
block in the wall will be, for example, 8 by 16 inches. 

Spec ifica tions 

The following specifications, known as American Concrete Insti- 
tute Standard No. 10, are standard specifications and building regula- 
tions for the manufacture and use of concrete architectural stone, 
building block and brick, and were adopted by the American Concrete 
Institute April 10, 1917. If these specifications are followed in the 
manufacture of concrete block, brick and architectural stone, a uni- 
formly high class product may always be expected. 



Adopted by Letter Ballot, April 10, 1917 


1. Concrete architectural stone and building blocks for solid or hollow 
walls and concrete brick made in accordance with the following specifications 
and meeting the requirements thereof may be used in building construction. 

2. Tests, — Concrete architectural stone, building blocks for hollow and 
solid walls and concrete brick must be subjected to (a) Compression and (b) 
Absorption tests. All tests must be made in a testing laboratory of recognized 

3. Ultimate Compressive Strength. — (a) Solid concrete stone, building 
blocks and brick. In the case of solid stone, blocks and brick, the ultimate 
compressive strength at 28 days must average not less than fifteen hundred 
(1,500) lb. per. sq. in. of gross cross-sectional area of the stone as used in the 
wall and must not fall below one thousand (1,000) lb. per sq. in. in any test. 

(b) Hollow and two piece building blocks. The ultimate compressive 
strength of hollow and two piece building blocks at 28 days must average one 
thousand (1,000) lb. per sq. in. of gross cross-sectional area of the block as 
used in the wall, and must not fall below seven hundred (700) lb. per sq. in. in 
any test. 

4. Gross Cross-Sectional Areas. — (a) Solid concrete stone, blocks and 
brick. The cross-sectional area shall be considered as the minimum area in 

(b) Hollow building blocks. In the case of hollow building blocks the 
gross cross-sectional area shall be considered as the product of the length by 
the width of the block. No allowance shall be made for the air space of the 

(c) Two piece building blocks. In the case of two piece building blocks, 
if only one block is tested at a time, the gross cross-sectional area shall be 
regarded as the product of the length of the block by one-half of the width 
of the wall for which the block is intended. If two blocks are tested together, 
then the gross cross-sectional area shall be regarded as the product of the 
length of the block by the full width of the wall for which the block is 

5. Absorption.— The absorption at 28 days (being the weight of the water 
absorbed divided by the weight of the dry sample) must not exceed ten (10) 
per cent when tested as hereinafter specified. 

6. Samples.— At least six samples must be provided for the purpose of 
testing. Such samples must represent the ordinary commercial product. In 
cases where the material is made and used in special shapes and forms too 
large for testing in the ordinary machine, smaller specimens shall be used as 
may be directed. Whenever possible the tests shall be made on full sized 



7. Compression Tests. — Compression tests shall be made as follows: The 
samples to be tested must be carefully measured and then bedded in plaster of 
paris or other cementitious material in order to secure uniform bearing in the 
testing machine. It shall then be loaded to failure. The compressive strength 
in pounds per square inch of gross cross-sectional area shall be regarded as 
the quotient obtained by dividing the total applied load in pounds by the gross 
cross-sectional area, which area shall be expressed in square inches computed 
according to article 4. 

When such tests must be made on cut sections of blocks, the pieces of the 
block must first be carefully measured. The samples shall then be bedded to 

secure uniform bear- 
ing, and loaded to fail- 
ure. In this case, how- 
ever, the compressive 
strength in pounds per 
square inch of net area 
must be obtained and 
the net area shall be 
regarded as the mini- 
mum bearing area in 
compression. The av- 
erage of the compres- 
sive strength of the 
two portions of blocks 
shaH be regarded as 
the compressive 
strength of the 
samples submitted. 
This net compressive 
ctrength shall then be 
reduced to compressive 
strength in pounds per 
square inch of gross 
cross-sectional area as 
The net area of a full sized block shall be carefully calculated and the total 
compressive strength of the block will be obtained by multiplying this area 
by the net compressive strength obtained above. This total gross compressive 
strength shall be divided by the gross cross-sectional area as figured by article 
4 to obtain the compressive strength in pounds per square inch of gross cross- 
sectional area. 

When testing other than rectangular blocks, great care must be taken to 
apply the load at the center ol gravity of the specimen. 

8. Absorption Tests. — The sample shall be first thoroughly dried to a con- 
stant weight at a temperature not to exceed two hundred and twelve (212) 
degrees Fahrenheit, and the weight recorded. After drying the sample shall 
be immersed in clean water for a period of forty-eight hours. The sample 
shall then be removed, the surface water wiped off, and the sample re-weighed. 
The percentage of absorption shall be regarded as the weight of the water 

Hydra-Stone block residence in Evanston, III 
u ith black granite. 

Block faced 


absorbed divided by the weight of the dry sample multiplied by one hundred 

9. Limit of Loading. — (a) Hollow walls of concrete building blocks. The 
load on any hollow walls of concrete blocks, including the superimposed weight 
of the wall, shall not exceed one hundred and sixty-seven (167) lb. per sq. in. 
of gross area. If the floor loads are carried on girders or joists resting on 
cement pilasters filled in place with slush concrete mixed in proportion of one 
(1) part cement, not to exceed two (2) parts of sand and four (4) parts of 
gravel or crushed stone, said pilasters may be loaded not to exceed three 
hundred (300) lb. per sq. in. of gross cross-sectional area. 

(b) Solid walls of concrete blocks. Solid walls built of architectural stone, 
blocks or brick and laid in portland cement mortar or hollow block walls filled 
with concrete shall not be loaded to exceed three hundred (300) lb. per sq. in. 
of gross cross-sectional area. 

Concrete block residence, Decatur, Ind., in which granite-faced Ideal concrete block 

were used. 

10. Girders and Joists. — Wherever girders or joists rest upon walls in such 
a manner as to cause concentrated loads of over four thousand (4,000) lb. the 
blocks supporting the girders or joists must be made solid for at least eight 
(8) in. from the inside face of the wall, except where a suitable bearing plate 
is provided to distribute the load over a sufficient area to reduce the stress so 
it will conform to the requirements of article 9. 

When the combined live and dead floor loads exceed sixty (60) lb. per sq. ft., 
the floor joists shall rest on a steel plate not less than three-eighths (y H ) of an 
inch thick and of a width one-half to one inch less than the wall thickness. In 
lieu of said steel plate the joists may rest on a solid block which may be three 
(3) or four (4) in. less in wall thickness than the building wall, except in 
instances where the wall is eight (8) in. thick, in which cases the solid blocks 
shall be the same thickness as the building wall. 



11. Thickness of Walls.— (a) Thickness of bearing walls shall be such as 
will conform to the limit of loading given in article 9. In no instance shall 
bearing walls be less than eight (8) in. thick. Hollow walls eight (8) in. thick 
shall not be over sixteen (16) ft. high for one story or more than a total of 
twenty-four (24) ft. for two stories. 

(b) Walls of residences and buildings commonly known as apartment build- 
ings not exceeding four stories in height, in which the dead floor load does not 
exceed sixty (60) lb. or the live load sixty (60) lb. per sq. ft., shall have a mini- 
mum thickness in inches as shown in Table 1. 






No. of 






























Small garage built of Ideal rock- faced concrete block, corners and window trim being of 

white -faced plain block. 

12. Variation in Thickness of Walls. — (a) Wherever walls are decreased in 
thickness the top course of the thicker wall shall afford a solid bearing for the 
webs or walls of the course of the concrete block above. 

13. Bond and Bearing Walls. — Where the face wall is constructed of both 
hollow concrete blocks and brick, the facing shall be bonded into the backing, 




either with headers projecting four (4) in. into the brick work, every fourth 
course being a header course, or with approved ties, no brick backing to be 
less than eight (8) in. thick. Where the walls are made entirely of concrete 
blocks, but where said blocks have not the same width as the wall, every fifth 
course shall overlap the course below by not less than four (4) in. unless the 
wall system alternates the cross bond through the wall in each course. 

14. Curtain Walls. — For curtain walls the limit of loading shall be the same 
as given in article 9. In no instance shall curtain walls be less than eight (8) 
in. in thickness. 

Dairy building built of Myer interlocking concrete block covered with stucco. 

15. Party Walls. — Walls of hollow concrete blocks used in the construction 
of party walls shall be filled in place with concrete in the proportion and 
manner described in article 9. 

16. Partition Walls. — Hollow partition walls of concrete blocks may be of 
the same thickness as required in hollow tile, terra cotta or plaster blocks for 
like purposes. 

NOTE,— Much valuable information on the subject of concrete block, brick and 
other cast concrete products can be found in a book entitled " Concrete Stone Manu- 
facture ," by Harvey Whipple, published by the Concrete— Cement Age Publishing 
Co., Detroit. This book may be obtained from the publishing company mentioned 
for Wm.$1.5Q 




Anchor Concrete Stone Co., Columbus, Ohio. 

Baute Concrete Machine Co., 402 West Main Street, Benton Harbor, 

Brandell Co., Union Central Tower, Cincinnati, Ohio. 
Century Cement Machine Co., Rochester, N. Y. 
W. E. Dunn Manufacturing Co., 410 Twenty-fourth Street, Holland, 

Eberling Machinery Co., Williamson Building, Cleveland, Ohio. 
Ferguson Synstone Co.. Waterloo, Iowa. 
Flexo-Concrete Mold Co., Cedar Rapids, Iowa. 
Francis Machinery Co., 5 Market Street, St. Louis, Mo. 
Hayden Automatic Block Machine Co., 112 West Broad Street, 

Columbus, Ohio. 
Helm Brick Machine Co., Cadillac, Mich. 
Hydro-Stone Co., 231 Insurance Exchange, Chicago, 111. 
Ideal Concrete Machine Co., 1304 Monmouth Avenue, Cincinnati, 

Kramer Automatic Tamper Co., Peoria Heights, 111. 
M. & M. Concrete Machinery Co., MHpMHI Clevcl&ad, O. 
Multiplex Concrete Machine Co., Elmore, Ohio. 
Northwestern Steel & Iron Works, Eau Claire, Wis. 
Peters-Eastman-Greer Co., Indianapolis, Ind. 
Zagelmeyer Cast Stone Block Machinery Co., 81 Crump Avenue, Bay 

City, Mich. 

Concrete block are adaptable to housing developments where large numbers ot building* 
are needed quickly. I he above houses hate been finished uiiti ttto « t oat. 



Six-apartment building at Ottawa, Ontario fen-inch Ideal block used it 
eight-inch for the remainc 

iutomobiU warehouse lit 

n M.u-A. (M t91'4 


Concrete Brick 

Adaptability of Concrete Brick 

Concrete brick are suitable for many classes of structures. They 
have ample strength and can be made of any required density. Varia- 
tions in density are sometimes necessary in order to insure firm bond- 
ing with mortar when laid up in the wall. Varying degrees of density 
are secured by varying the grading of the aggregate and the amount 
of cement used within certain limits. Like concrete block, concrete 
brick may also be faced. Facings vary in thickness from 1 16 inch to 
1 inch or more and can be of a variety of colors obtained in a manner 
similar to that already described when discussing surface finish of 
concrete block on page 6. 

Concrete block foundation and concrete brick walls. House at Crawford. Xeb. H alts 
are double and surface finish was secured by using white cement and marble screenings. 

If the waterproof qualities of the concrete brick wall are to depend 
on the facing of the brick, and if the body of the brick is made slightly 
porous to afford a better bond with the mortar joints, then the face 
should be deep enough to extend back of the line of a raked joint, if 
such joints are to be used in the work. 

Principles of Manufacture 

The same general rules apply to the manufacture of concrete brick 
as apply to the manufacture of concrete block, although the aggregate 
ranges smaller, y% inch usually being the maximum. Different proc- 


esses are used to make concrete brick. These range from pressing a 
suitable mortar into molds or compacting the mixtures in machines 
exerting great pressure on a stiff, plastic or semi-dry mixture of 
concrete. The pressure process produces, with properly proportioned 
concrete, a very dense, strong brick, comparing favorably in appear- 
ance and quality with the best brick manufactured of any other 

Concrete products manufacturers will profit most by making con- 
crete products of high quality. Neither cement nor labor should be 
spared to secure proper density, strength, curing and appearance. 

When purchasing any kind of machinery it is well to bear in mind 
that price is not necessarily a measure of quality or desirability. A 
careful consideration should be given to the merits of a machine as 
well as to its price. In using semi-dry mixtures of concrete, con- 
siderable tamping must be done or considerable pressure exerted to 
compact materials into a homogeneous mass. The same applies to 
stiff, plastic mixtures, and with such processes excellent results will 
be obtained when the products are cured under the conditions of mois- 
ture and warmth described on page 9. 


Besser Manufacturing Co., Alpena, Mich. 

Concrete Machine Corporation, Securities Bldg., Des Moines, Iowa. 

W. E. Dunn Manufacturing Co., 410 Twenty-fourth Street, Holland, 

Helm Brick Machine Co., Cadillac, Mich. 
Northwestern Steel & Iron Works, Eau Claire, Wis. 
Peerless Brick Machine Co., Minneapolis, Minn. 
Raber & Lang Manufacturing Co., Kendallville, Ind. 
Shope Brick Co., Portland, Ore. 

Let Us Help You 

The Cement Products Bureau of the Portland Cement Association 
devotes its efforts to helping those manufacturing concrete block, 
brick, drain tile, sewer pipe and other concrete products to improve 
methods of manufacturing and even assisting where possible in de- 
veloping markets or helping to solve marketing problems. Such 
services as the Bureau can render are yours for the asking. 

Oct"' ■ 

Concrete Drain Tile 
Concrete Sewer Pipe 
Concrete Pressure Pipe 
Cement Stave Silos 
-* Concrete Fence Posts 

Are concrete products for which there is a large 
and growing demand. Many manufacturers of 
concrete building block and brick might profita- 
bly add one or more of the above to their plant 

Our booklets 

Concrete Drain Tile for Land Drainage 

Concrete Sewers 

Concrete Pressure Pipe 

Cement Stave Silos, and 

Concrete Fence Posts 
will suggest the possibilities in these fields. 

If interested in taking up the manufacture of 
any of these products, ask our Cement Products 
Bureau to confer with and help you. 

Concrete for Permanence 


Offices at 

If IK 

\» M 



imvii nrvM